After a wet April, this year’s allergy season in the Willamette Valley seemed like it might be delayed. But now that we’ve had a few sunny weeks, some pollen counts are ahead of normal.

Pollen counts are in the moderate range this week for trees and grass, according to Dr. Kraig Jacobson with Oregon Allergy Associates. He said warm, dry weather has sped up deciduous tree development.

“The tree pollens usually finish by the end of May and we’re seeing them taper off pretty rapidly here,” he said. ”So we’re seeing an early end to the tree season.”

Jacobson said grass pollen season typically runs from late May to July, but rain preceding that season can impact allergy sufferers.

“One pollen particle can become 10,000 fragments,” he told KLCC. ”Those fragments can go straight down in the lower airway and cause chest tightness and wheezing.”

He said the fragments don’t show up well in pollen counts, so the actual count may be higher than the measured numbers. Later in the season, Jacobson said, grass pollen grains don’t burst into fragments, because the makeup of the pollen changes.

Why do we have allergies?

If someone has breathing issues, according to Jacobson, they should see a physician, because it should be treated with prescription medication.

Jacobson said the usual symptoms of allergies are sneezing, itchy eyes and nose, and nasal congestion.

“It can be overwhelming enough that it feels like one’s getting actually sick and that’s where the name ‘hay fever’ came from,” he said.

Though, he noted, with allergies, people don’t develop a fever.

Karen Richards is a reporter with KLCC. This story comes to you from the Northwest News Network, a collaboration between public media organizations in Oregon and Washington.

It is part of OPB’s broader effort to ensure that everyone in our region has access to quality journalism that informs, entertains and enriches their lives. To learn more, visit our journalism partnerships page.

News Source : https://www.opb.org/article/2025/05/08/allergy-season-is-accelerating-in-the-willamette-valley/